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Titel |
The variability of methane, nitrous oxide and sulfur hexafluoride in Northeast India |
VerfasserIn |
A. L. Ganesan, A. Chatterjee, R. G. Prinn, C. M. Harth, P. K. Salameh, A. J. Manning, B. D. Hall, J. Mühle, L. K. Meredith, R. F. Weiss, S. O'Doherty, D. Young |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 21 ; Nr. 13, no. 21 (2013-11-04), S.10633-10644 |
Datensatznummer |
250085783
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Publikation (Nr.) |
copernicus.org/acp-13-10633-2013.pdf |
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Zusammenfassung |
High-frequency atmospheric measurements of methane (CH4),
nitrous oxide (N2O) and sulfur hexafluoride (SF6)
from Darjeeling, India are presented from December 2011
(CH4)/March 2012 (N2O and SF6) through
February 2013. These measurements were made on a gas chromatograph
equipped with a flame ionization detector and electron capture
detector, and were calibrated on the Tohoku University, the Scripps
Institution of Oceanography (SIO)-98 and SIO-2005 scales for
CH4, N2O and SF6, respectively. The
observations show large variability and frequent pollution events in
CH4 and N2O mole fractions, suggesting significant
sources in the regions sampled by Darjeeling throughout the year.
By contrast, SF6 mole fractions show little variability and
only occasional pollution episodes, likely due to weak sources in
the region. Simulations using the Numerical Atmospheric dispersion
Modelling Environment (NAME) particle dispersion model suggest that
many of the enhancements in the three gases result from the
transport of pollutants from the densely populated Indo-Gangetic
Plains of India to Darjeeling. The meteorology of the region varies
considerably throughout the year from Himalayan flows in the winter
to the strong south Asian summer monsoon. The model is consistent
in simulating a diurnal cycle in CH4 and N2O mole
fractions that is present during the winter but absent in the summer
and suggests that the signals measured at Darjeeling are dominated
by large-scale (~100 km) flows rather than local
(<10 km) flows. |
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